- Metal alloys can now be efficiently injection moulded
- Components with completely new characteristics
- Higher elasticity than titanium
- Application: from medical to aerospace
Liquidmetal stands for a class of material with completely new characteristics. As the exclusive machinery manufacturing partner of Liquidmetal Technologies, USA, the company Engel is the only provider worldwide to offer such a system for the injection moulding of Liquidmetal materials. Engel presented this technology to the public at the recent Engel Symposium 2015 for the first time.
Components with completely new characteristics
Liquidmetal: the zirconium alloys feature an amorphous, i.e. non-crystalline, structure, which is why they are referred to as metallic glasses. Components made from these materials are extremely hard, but at the same time very elastic, which leads to very good recovery behaviour. For example, the elasticity of steel is 0.2 percent and for titanium it is 1 percent, while the value for components made of Liquidmetal alloys is 2 percent. In addition, the materials are characterised by their low specific weight and very good corrosion resistance. This range of characteristics predestines the alloys for use in precision components which are subjected to high mechanical stresses.
Metal slugs are melted inductively under high vacuum
In order to process these materials using injection moulding, Engel has developed a new injection moulding machine based on the existing all-electric machine series Engel e-motion. The injection unit is the main difference between a Liquidmetal machine and a conventional injection moulding machine for plastics processing. The Liquidmetal alloys are available in the form of slugs cut from round rods. These blanks are automatically fed into a melting chamber where the material is melted inductively under high vacuum conditions. Instead of a screw, the machine has a piston with which the molten metal alloy is injected into a thermo-regulated mould. Very rapid cooling under exclusion of oxygen leads to the forming of the amorphous structure. Standard robots are used to remove the finished parts. The sprue can be removed with the help of a water-jet cutting machine or mechanical shears.
Alternative to metal injection moulding (MIM) and CNC processing
Liquidmetal can be considered as an alternative to metal injection moulding (MIM) and CNC processing.
In CNC-processing, individual metal components are machined out of a metal block, for example by milling, drilling, grinding and turning. In this way, complex three-dimensional precision parts with a high-quality surface finish can be produced. In comparison to injection moulding, however, this is a time- and cost-intensive fabrication process.
The MIM process is also an injection moulding procedure, however, the materials processed are not metal alloys, but rather metal/plastic powders. The plastic is removed thermally after injection moulding and the finished component is obtained by a sintering process. Furthermore, the surface is often rough from the sintering process and may require reworking. These additional process steps may take up some time depending on the wall thickness.
These disadvantages are eliminated when the Liquidmetal technology is used. It provides ready-to-install precision components with a very high surface finish quality. The cycle times is between two and three minutes and are thus significantly shorter than the processing time needed for CNC processing. Another advantage is that there is no waste accumulated in Liquidmetal processing because the sprues can be recycled.
Applications: from medical technology to aerospace
Engel sees good potential for Liquidmetal Technology in the field of medical technology, which is why at the symposium parts for medical forceps were produced. Endoprostheses like hip joints or stents are also conceivable. Due to the very good mechanical properties of the material, very robust components can also be produced with very thin wall thickness. In addition, there are applications in the fields of electronics, aerospace, military technology and sports equipment. It has already found a first area of application in the entertainment electronics and watch industries.
The licenses for the new method are obtained from Liquidmetal Technologies, and Engel delivers injection moulding system to the licensed partners.